I cannot help You with MU since I never tested it, to be honest i never even installed wordpress MU. This script of mine was created for a specific purpose and it is not a plugin at all... however it serves to lot of people as quite a good base for some of their own projects.
When I wrote the script I used the wordpress 'user contact fields' only because I could then easily manipulate data throughout my theme... I believe that You could easily create another MySQL table specificaly for user data you want to save.
The other and maybe more simple option would be to duplicate my plugin and create 2 custom "Profile pages", one for complayn data, and other for user. You would have to make sure that variables used are not the same... I think you could easily include changing avatar picture and password in other profile page.
So basically, You would store all data in default "profile" which would be hidden for end user, and display that same data on 2 different custom profile pages...
Hope that helps and I wish you best of luck ;)